利用和频振动光谱与电化学方法探测离子液体-电极界面处的电场

Probing electric fields at the ionic liquid-electrode interface using sum frequency generation spectroscopy and electrochemistry.

作者信息

Baldelli Steven

出版信息

J Phys Chem B. 2005 Jul 14;109(27):13049-51. doi: 10.1021/jp052913r.

Abstract

The arrangement of ions at the platinum electrode in the room-temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate has been determined using sum frequency generation vibrational spectroscopy (SFG), electrochemical impedance spectroscopy (EIS), and the vibrational Stark effect. The results indicate that CO adsorbed on the Pt electrode has a Stark shift of 30-35 cm(-1)/V in the ionic liquid. The potential of zero charge (PZC) of the ionic liquid-Pt system is approximately -500 mV (vs Ag wire), with a capacitance of 0.12 F/m2. Further, polarization-dependent SFG experiments suggest the ions reorganize at the surface depending on the electrode charge. In combination, all these results indicate that the ions of a neat ionic liquid are organized in a Helmholtz layer at the electrified metal electrode interface.

摘要

利用和频振动光谱（SFG）、电化学阻抗谱（EIS）以及振动斯塔克效应，确定了室温离子液体1-丁基-3-甲基咪唑四氟硼酸盐中铂电极上离子的排列情况。结果表明，在离子液体中吸附在铂电极上的CO具有30 - 35 cm⁻¹/V的斯塔克位移。离子液体 - 铂体系的零电荷电位（PZC）约为 -500 mV（相对于银丝），电容为0.12 F/m²。此外，偏振相关的SFG实验表明，离子会根据电极电荷在表面重新排列。综合来看，所有这些结果表明，纯离子液体的离子在带电金属电极界面处的亥姆霍兹层中有序排列。